DefinitionMusculoskeletal system is made up of

muscles, bones, and the tissues that connect them.

It functions to provide:Structure – gives shape and sizeProtection – protects fragile tissueMineral Reserve - calcium and phosphorusBlood Cell Production – bone marrow is housed

in long bones which produces blood cells

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Bone Structure Parts of a long bone Epiphysis - very ends; covered with articular

cartilage Metaphysis - middle; transition area Diaphysis - shaft of a long bone

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Bone StructureLong bones are known as compact bones

Dense or compact outer shell of the boneThe more force placed on the bone, the thicker

this layer will be Femur – The shaft of the bone will be thicker as this

is where the majority of strain will occur

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Bone StructureInside the compact bone is loosely arranged

bone called spongy boneFound only in long bones, not flat bonesFills only the ends of the bones

Created of spincules that are randomly assortedProvides strength while making the bone light-

weight

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Bone StructureThe medullary cavity - hollow shaft of the

boneHolds the bone marrow which is the site of

blood cell production

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Bone StructurePeriosteum is a thin connective tissue that

covers the bonesBlends into the tendons and ligaments binding

them to the bone Area of the bone covered in cartilage does not have

periosteum covering it – Cartilage provides protection

Endosteum is a similar connective tissue that protects open spaces within the bone

Periosteum and endosteum provide the cells needed for repair of damage

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Bone StructureDried bone is composed of:

70% inorganic material Mostly calcium and phosphorus Provide hardness and strength

30% organic components Composed of collagen and cells Provides a level of elasticity – ability to bend

slightly

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Now a word from our sponsors…

Providing you with the terms you need to know!

Oste/o – bone-blast – embryonic-cyte – cell-clast - break

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Bone StructureThree types of bone cells

Osteoblasts – (bone embryo) young bone cells which lay down collagen matrix Once encased in matrix develop into osteocytes

Osteocytes – (bone cell) maintain the bone matrix

Osteoclasts – (bone break) allow for minerals to be released from the bone

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Use it!Osteoporosis?

Oste/o – bone -porosis – passage or porous condition

When bones loose the normal density which leads to decreased bone mass How?

Osteoclasts release minerals into the blood stream as needed, if a bone does not redeposit minerals back into the bone it becomes weak!

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Use it!Once a bone becomes to thin due to removal

of minerals, it is easier to break!

If caused by disuse of limb (animal in cast) reversible once the animal begins to use the limb.

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Bone StructureBone is composed of a collection of

microscopic units call osteons.In the center of the osteons there is a canal

that hold blood vessels, nerves, and lymphaticsBone is laid down in circular patterns around

this channel Within this layer are osteocytes that maintain the

bone matrix Many osteons joined together form layers of bone

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